Feedback divider for fluid amplifier

ABSTRACT

This invention relates to pure fluid amplifiers having dynamic feedback dividers for providing a feedback which contributes assistance to the boundary layer lock-on phenomena.

. .[21] ApplQNo.

United States Patent Raymond W. Warren McLean, Va.;

Ralph .G. Barclay, John Gerald Moorhead,

Silver Spring, Md.

June 12, 1964 said Warren assignor to the United States of America asrepresented by the Secretary of the Army A division of Ser. No. 222,748,Sept. 10,

1962, now Patent No. 3,397 .713.

[72] Inventors [22] Filed [45] Patented [73] Assignee [54] FEEDBACKDIVIDER FOR FLUID AMPLIFIER -4 Claims, 1 Drawing Fig.

52 us; Cl. 137/815 [51] Int. Cl Fl5c 1/08 [50] Field ofSearch 137/815[56] References Cited UNITED STATES PATENTS 1,658,797 2/1928 Charretteet al.

3,181,546 5/1965 Boothe 137/815 3,225,780 12/1965 Warren et a1. 137/81.53,192,938 7/1965 Bauer l37/81.5 3,244,370 4/1966 Colston 137/81.5X

Primary Ekaminer-SamuelScott Attorneys Harry M. Saragovitz, Edward JKelly, Herbert Bet] and J. DqEdgerton ABSTRACT: This invention relatesto pure fluid amplifiers having dynamic feedback dividers for providinga feedback which contributes assistance to the boundary layer lock-onphenomena.

' vider'for Fluid Amplifiers.

The invention described herein may be manufactured and I used by or forthe Government of the United States of America for Governmental purposeswithout the payment to me of any royalties thereon. j p 3 This inventionrelates to fluid amplifiers and more particularly,to dynamicfeedhackdividers in fluid amplifiers.

1968, entitled'Feedback Di- In previous fluid amplifiers, the dividerswhich separate the 2 output channels were substantially wedge shapedwith the pointed edge of the wedge aligned with the power nozzle in sucha mar ner that the divider would separate the interaction region intotwo output channels; Wall of the flow from the power stream could not becontained in'one output channel, the divider would, separate. the powerstream into a majority flow and a minority flow into the outputchannels. The favored channel was the channel which had the majority ofthe power stream' flow. Favoring of one output channel over the otherwas a function of the 'symmetryof the amplifier elements, the smoothnessof the surfaces exposed to the power stream flow the divergence of theoutput channels', the amount of control provided directly on-the stream,boundary layer effects, loading of the outputs, and the like.2 0ncefavored, the power stream would remain in the favoredioutput channeluntil a control signal was provided to switch it tothe other channel.This control signal couldioriginate externally of the amplifier,

. could bea portion of the power stream. feedback to the inbility thatwouldprevent the stream from remaining in a favored channeluntilswitching to the other channel is desired. One of these causes isencountered when the amplifier is connected to a-load. The resistance inthe system could be suchthatthe output'channel would no longer carry allof y the power stream as it w'o'uld'in' an unloaded condition. Underthese circumstances, the return of the-excess power stream A furtherobject of this invention is to provide a divider which eliminates theneed of counterflow in the output channel not favored by the powerstream in a fluid amplifier so as to enable the use of the fluidamplifier in outer space or other low-pressure environments.

A still further object of this invention is to provide a divider in afluid amplifier which provides a momentum in a feedback flow whichserves as a control signal.

The FlG. shows one embodiment of this invention.

Briefly, the-purposes of thisinvention are accomplished by the provisionof a divider in a fluid amplifier which feeds back a part of the powerstream in one receiver to reinforce the forces diverting the powerstream into said one receiver. Feedback is against a blunt or curved endof the divider to provide a pressure seal over the entrance to the notfavored output channel and also to reinforce the diverting forces on thepower stream which direct it into the favored channel. A vortex isgenerated which further enhances the reinforcement and provides adynamic characteristic.

The bistable amplifier shown in FIG. 1 has power jet nozzle,

opposed control nozzles, and a pair of output receiver channels 42 and43. Separating the receivers 42 and 43 is a divider 'with a concavecurved surface 41. Allof the downstream material of the divider has beenremoved to present the surface 42 as the curved leading edge of thedivider between output receivers 42 and 43. Between the curved surface41 and the interaction chamber 47, there isno divider structure. The

- curved structure4l is concave when viewed from the power down thefavored channel against gthe flow of the power I stream can causeperturbations and turbulences that wouldpromote instability; Since allthe'fluid does not get out into the load, some of the fluid leaks aroundthe divider and-out through the other channel. Oscillations as well asother instabilities may result-Further, the direction of all of thepower stream into a favored output channel and maintaining it there.

could require an excessive amount of control signal, and could requirethat the control signal be applied for an excessive amount of time.

- Accordingly, this invention is'directed to improvements influidarnplifier dividers which provide:- increased stability in a fluidamplifier; reliability of memory functions; an assist to'the boundarylayer lock-on phenomena; the reduction or elimination of counter flowthrough theunfavored output channel as, well as the need. therefor:momentum in a feedback ,flow

which serves as a locking control signal; feedback signals which havevector properties, and feedback signals which operate in the manner ofaservo feedback signal.

It is, therefore, an object of this invention-to provide an improveddividerin a fluid-operated device.

. L A further object of this, invention is to provide a divider whichcontributes to the stability ofa fluid amplifier.

A still further object of this invention is to provide a divider whichenables reliability of memory functions in a fluid amplinozzle. Theinteraction chamber47 is'bounded by the divider tional in the art, thecontrol nozzles control which receiver channel wall the power jetlatches on to.

In operation, the divider curved edge 41 .forms a vortex and directs thefeedback flow down alongthe unfavored receiver receiver sidewall, and inthe vicinity of the sidewall, turns to travel near the sidewall in adirection away from the interaction chamber 47 as shown by flow'line 44.A majority of the feedback flow is directed into the interaction chamber47 as shown by flow line 44. A majority of the feedback flow is directedinto the interaction chamber. where a vortex 45 is formed by curved flowof the feedback fluid to provide momentum to the power stream inreceiver 42 to further lock the power stream therein. The remainder ofthe flow distributes through the remainder of the interaction chamber 47in the circular paths indicated by the remaining arrows 46.

The flow line 44 indicates a pressurearea which is a barrier sufficientto maintain power stream integrity even if the pressure availableexterior to the fluid amplifier is very low. This permits the amplifierto operate in outer space. The vortex 45 and the lock-on assist vectors46 would be maintained in the absence of a counterpressure down theunfavored receiver 43.

The fluid amplifier in this disclosure is the wall effect amplifier Thebasic bistability comes about because the stream entrains away fluid andproduces a low-pressure separation bubble on the wall. This is indicatedin the drawing by the exposure of the short bottom end of the sidewallof the favored receiver to which the power stream is shown not attached.The entrainment and the bubble provide a low-pressure region V whichallows the higher pressure on the opposite side of the power stream tohold the stream against the favored sidewall. The effectiveness of theholding of the stream against the sidewall depends on the pressuredifferential on the two sides of the stream. The feedback divider splitsoff part of the stream and directs it so as to increase the pushingpressure lock-on. ln the embodiment shown, should the stream move awayfrom the bistable position, more of the stream is split off and thepushing pressure is increased forcing the stream back into its bistableposition. The action of this restoring pressure that is generated issimilar to the action ofa servoloop.

Fluid amplifiers of the type of which this invention is an improvementare more adequately disclosed in the copending application entitledFluid Amplifier Employing Boundary Layer Effect, Ser. No. 58,188, filedOct. 19, 1960 and now US. Pat. No. 3,396,6l9 revised Aug. 13, 1968. byRaymond W. Warren et al. Mr. Warren is one of the inventors of thisapplication.

So, it is seen that we have provided an improved divider in a fluidamplifier. The divider improvements of this disclosure contribute tostability and enable reliability of memory functions in a fluidamplifier. The counterflow in the not-favored output channel is reducedor eliminated and operation in outer space is provided. The lock-onphenomenon is reinforced by the feedback flow and by the momentum ofsuch flow. The feedback flow has vector properties. The counterflowaround the pointed edge of the divider has been eliminated and thewandering of the power stream has been used to provide a pressureproportional to such wandering to reinforce the power stream in a stableposition in the manner of a servoloop.

It will be apparentthat the embodiment shown is only exemplary and thatvarious modifications can be made in construction and arrangement withinthe scope of the invention as defined in the appended claims.

The divider 41 can be concave as shown, blunted as said above, squaredoff, or in any shape that will provide the flow pattern needed toreinforce the lock-on pressure differential and provide stabiltiy. Anexample of such a flow pattern is shown by arrows 46 and vortex 45.Dividers shaped like a flat open box, with the open end directed towardthe power stream, will provide a flow pattern that is equivalent to thatprovided by a concave divider.

We claim:

1. In a fluid amplifier:

a. a fluid power source for producing a fluid stream;

b. A pair of divergent receiver means;

c. means for directing said power stream toward said receiver means;

d. divider means for separating said pairof receiver means;

e. said divider means being a solid element having a pair of divergentsides which form the inner side'sfof said pair of receiver means; andhaving'a thirdis'ide connecting the closer ends of the divergent si s,and I, I I

f. said third side providing a feedbaclg'flowltoreinforce thecontinuance of power was iii one of said receiver means. i i

a. a fluid power source for producingzi uid stre'a'm;

b. a pair of divergent receiver meansi i c. means for directing saidpower stream toward said receiver means; I

d. divider means for separating said pair of receiver means;

e. said divider means being a solid element having a pair or receivermeans, and having a third side connecting th closer ends of thedivergent sides; and i f. said third side being arcuate in shape.

a. a fluid power source for producing a fluid stream;

b. a pair of divergent receiver means;

c. means for directing said power stream toward said receiver means;

d. divider means for separating said pair of receiver means;

ersaid divider means being a solid element having a pair of divergentsides which form the inner sides of said pair of receiver means,andhaving a third side connecting the closer ends ofthe divergent sidesand f. said third side being concave in shape with respect to said powersource. v

4. A fluid device comprising an inlet for supplying power fluid, a pairof outlets, a pair of control inlets for.directing said power fluid to aselected outlet, and a vortex chamber all leading from a common mixingchamber,lsaid vortex chamber being disposed intermediate said outletsand in alignment with said inlet to receive power fluid therefrom, saidvortex chamber being dimensioned to create a vortex movement of fluidtherein with a portion of said fluid being directed to said selectedoutlet to maintain said fluid at said selected outlet after theapplication of fluid from said control inlets has terminated, saidcontrol inlets being disposed at substantially right angles with respectto said inlet and said vortex chamber, said outlets being angularlydisposed away from said inlet-.on opposite sides of said vortex chamberand between said vortex chamber and said control inlets.

1. In a fluid amplifier: a. a fluid power source for producing a fluidstream; b. A pair of divergent receiver means; c. means for directingsaid power stream toward said receiver means; d. divider means forseparatiNg said pair of receiver means; e. said divider means being asolid element having a pair of divergent sides which form the innersides of said pair of receiver means; and having a third side connectingthe closer ends of the divergent sides; and f. said third side providinga feedback flow to reinforce the continuance of power stream in one ofsaid receiver means.
 2. In a fluid amplifier: a. a fluid power sourcefor producing a fluid stream; b. a pair of divergent receiver means; c.means for directing said power stream toward said receiver means; d.divider means for separating said pair of receiver means; e. saiddivider means being a solid element having a pair or receiver means, andhaving a third side connecting the closer ends of the divergent sides;and f. said third side being arcuate in shape.
 3. In a fluid amplifier:a. a fluid power source for producing a fluid stream; b. a pair ofdivergent receiver means; c. means for directing said power streamtoward said receiver means; d. divider means for separating said pair ofreceiver means; e. said divider means being a solid element having apair of divergent sides which form the inner sides of said pair ofreceiver means, and having a third side connecting the closer ends ofthe divergent sides; and f. said third side being concave in shape withrespect to said power source.
 4. A fluid device comprising an inlet forsupplying power fluid, a pair of outlets, a pair of control inlets fordirecting said power fluid to a selected outlet, and a vortex chamberall leading from a common mixing chamber, said vortex chamber beingdisposed intermediate said outlets and in alignment with said inlet toreceive power fluid therefrom, said vortex chamber being dimensioned tocreate a vortex movement of fluid therein with a portion of said fluidbeing directed to said selected outlet to maintain said fluid at saidselected outlet after the application of fluid from said control inletshas terminated, said control inlets being disposed at substantiallyright angles with respect to said inlet and said vortex chamber, saidoutlets being angularly disposed away from said inlet on opposite sidesof said vortex chamber and between said vortex chamber and said controlinlets.